The invention relates generally to accumulation conveyors and, more particularly, to pneumatically actuated accumulation conveyors.
Accumulation conveyors normally include conveying rollers that support product being conveyed and when rotated, transport the same in a particular direction. Positioned below the conveying rollers is an endless drive member, such as a composite belt, a padded chain, a linked belt, and the like, which is driven by a drive motor. The accumulation conveyor system is normally divided into a plurality of zones. Each zone of the conveyor is equipped with a product sensor for detecting the presence or absence of product at a particular position along the conveyor. Each of these sensors is operationally connected to a contact assembly positioned below the top run of the endless drive member. Each contact assembly includes a pneumatically, mechanically or electrically driven vertically reciprocal contact member which may be operated individually or be operationally interconnected with contact assemblies positioned in other zones of the conveyor.
In accordance with a particular control scheme dictating the selective movement of product along the conveyor, one or more of the contact assemblies are actuated to move the contact member into frictional contact with the endless drive member. When a particular contact member is in such frictional engagement with the endless drive member, the conveying rollers adjacent the control assembly are engaged by the top surface of the top run of the endless drive member and begin to rotate. This rotation in turn results in the transportation of product supported by the selected conveying rollers.
When it is desired to accumulate product within a particular zone of the conveyor the contact assembly within that zone vertically retracts, and hence moves out of driving engagement with the endless drive member. This in turn results in the disengagement of the top surface of the endless drive member from contact with the conveying rollers and thus, such conveying rollers cease rotation.
The endless drive member of the accumulation conveyor has a tendency to become misaligned with the contact assembly. Over the length of the conveyor, this misalignment may become pronounced and may cause the endless drive member to deviate from one or more contact members. This misalignment may be encountered whether using generally flat drive belts or V-shaped belts, i.e., belts having a protrusion formed on the lower surface. This deviation may even result in contact between the endless drive member and a side support rail, causing damage to both the endless drive member and the conveyor, as well as the inefficient conveyance of product.
Therefore, there exists a need for a contact assembly for an accumulation conveyor which overcomes the difficulties of the prior art while being exceptionally functional and economical to manufacture.
The invention is useful with an accumulation conveyor having an endless drive member, a plurality of conveying rollers and a plurality of contact assemblies configured to selectively reciprocally move into engagement with the endless drive member to move the endless drive member into engagement with the conveying rollers. According to an aspect of the invention, the contact assembly includes at least a portion configured to move in the plane of the endless drive member when in engagement with the endless drive member to thereby align the contact assembly and the endless drive member. Providing a contact assembly, a portion of which moves in the plane of the endless drive member, maintains the alignment between the contact assembly and the endless drive member, assuring that the endless drive member remains centered upon the contact assembly, and hence, maximizes efficient operation.
According to another aspect of the invention, an accumulation conveyor includes an endless drive member that is juxtaposed with a plurality of conveying rollers and travels in a particular plane. At least one sensor senses that the endless drive member is misaligned. At least one contact assembly is operably interconnected with the sensor and is selectively movable to bring the endless drive member into alignment with the associated contact assembly. The contact assembly includes a portion that is movable in the plane of the endless drive member. In this manner, the at least one contact assembly is configured to realign the endless drive member in response to the sensor sensing that the endless drive member is misaligned. The employment of a sensor operably connected to a contact assembly capable of realigning the endless drive member provides a reliable, effective control system for maintaining the alignment of the endless drive member.
According to yet another aspect of the invention, an accumulation conveyor includes a support member formed with at least one generally vertical guide member extending therefrom and carrying a force producing device. A contact member is supported by the support member and is moved into engagement with the endless drive member upon actuation of the force producing device. Engagement between the contact member and the endless drive member pivots the contact member about the at least one guide member to align the contact member with the endless drive member. This pivotal compliance maintains alignment between the contact member and the endless drive member, and hence prevents the endless drive member from moving off the contact member and potentially causing damage to the conveyor.
According to still yet another aspect of the invention, a contact assembly for an accumulation conveyor includes a support member, a force producing device carried by the support member, and a wheel assembly positioned between the force producing device and the conveying rollers. The wheel assembly includes at least one upstream roller and at least one downstream roller. Contact between the wheel assembly and the endless drive member pivots the wheel assembly about a substantially vertical axis between the upstream and downstream roller and closer to the upstream roller to thereby maintain alignment between the wheel assembly and the endless drive member.
According to still yet another aspect of the invention, an accumulation conveyor includes a force producing device carried by a support member, and a wheel assembly positioned between the force producing device and the support member. The wheel assembly is rotatably positioned on the at least one guide member and rotates about a generally vertical axis. The wheel assembly includes a first pair of contact rollers and a second pair of contact rollers. The first pair of contact rollers are positioned first in the direction of travel of the endless drive member, and are positioned a distance apart, whereby the distance is slightly larger than the width of the protrusion formed in the endless drive member. Contact between an inner surface of a contact roller of the first pair of contact rollers and the protrusion of the endless drive member pivots the platform to thereby maintain alignment between the platform and the endless drive member. Providing a pair of contact rollers attached to a pivoting platform, which are spaced so that engagement between the protrusion and the contact rollers pivots the platform to maintain alignment provides an effective and reliable structure for maintaining alignment between the platform and the endless drive member.
These and other objects, advantages, purposes, and features of the invention will become apparent upon review of the following specification in conjunction with the drawings.